As well as transmitting data, current packet-oriented networks are used increasingly for transmitting communication data or real-time communication data. The transmission of communication data via a packet-oriented network is often also referred to as Voice over IP or VoIP. The term VoIP thereby refers to a technology for transmitting useful data, such as voice, and an exchange of signaling data for controlling connections via packet-oriented networks.
Two standard protocols for the implementation of VoIP, specifically H.323 and SIP, are known for the packet-oriented transmission of communication data between two users and for switching users and providing performance features.
SIP (Session Initiation Protocol) is a standard proposed by the Internet Engineering Task Force (IETF) for signaling connections via packet-oriented networks and is currently predominantly deployed in the field of internet telephony and for further services such as conference interactions, event notification, message transmission, etc.
The standard H.323 is an international ITU-T standard (International Telecommunication Union—Telecommunication Standardization Sector) for voice, data and video communication via packet-oriented networks, ensuring mutual interoperability of proprietary products.
For the implementation of packet-oriented communication technologies in a communication system, the problem frequently occurs that the above-mentioned protocols H.323 und SIP have to coexist, in order to be able to link communication terminals operating according to the respective communication protocol. It is not however possible for a SIP communication terminal to communicate with an H.323-compatible communication terminal without the provision of further technical devices.
Previous VoIP solutions have been based on so-called standalone software. Standalone software refers to software installed in the communication terminal or—in more general form—in a client to process both signaling data and payload data. One disadvantage of such a solution is that any change to the communication protocol and any introduction of new additional performance features can only be implemented by updating said software at every terminal. For a company this measure requires a great deal of configuration work and therefore a significant cost expenditure.
A further problem is the complexity of said software. As new performance and service features are introduced, said software becomes more and more complex and extensive. The software implemented in the communication terminal—client software—not only has to identify newly added performance features, it must also be able to implement methods to execute said performance features.
With extensive standalone software, integration into applications not provided for communication purposes is problematic. To develop said applications, already existing VoIP functions generally have to be adapted or developed from new. Furthermore the integration of additional performance features from third party manufacturers is almost excluded.
Some VoIP applications provide programming interfaces for integration into other applications and these are known in specialist circles as Application Program Interfaces, API. However a further compilation process is generally required to integrate said programming interfaces into other applications.
The use of so-called gateways is known as a means to ensure the interoperability of the VoIP communication protocols H.323 and SIP. A gateway thereby converts signaling data based on the SIP protocol to a format suitable for H.323 and vice-versa. It is often the case here however that protocol elements of a respective communication protocol are incompatible with protocol elements of the other communication protocol. It is also often the case that one of the two communication protocols supports services, applications, processing methods, etc. which are not supported in the other communication protocol.
To avoid the problems associated with updating stand-alone software as discussed above, some service providers offer VoIP solutions as so-called web applications. Obtaining a so-called applet via a packet-oriented data network and integrating it in a browser environment in the form of a so-called plug-in allows the execution of a VoIP functionality via a web browser. Such an above-mentioned execution improves the above-mentioned update problem but offers no opportunity for seamless integration into any applications.